Field of Use
The present disclosure relates generally to impedance matching networks, and more specifically to an impedance matching device incorporating a coupled resonator structure.
Description of the Related Art
Various electronic systems employ power amplifiers for increasing the power of signals such as high frequency signals. In a wireless communication system, a power amplifier is usually the last amplifier in a transmission chain (i.e., the output stage). High gain, high linearity, stability, and a high level of efficiency—the ratio of radio frequency (RF) output power to direct current (DC) power—are characteristics of an ideal amplifier.
In the area of RF circuit design, amplifier operation can be optimized by providing an impedance match at the input or output of the amplifier. The failure to achieve such an impedance match can be problematic in the design of electronic equipment (e.g. audio, wireless communications, etc.), where un-matched impedances can substantially reduce amplifier performance and signal quality. Impedance matching can be accomplished by transforming either the impedance at an output of a package or device supplying an input signal to the amplifier or at the input to the amplifier itself.
To date, various impedance matching networks have been implemented for achieving impedance matching in an RF circuit. Typically, such networks utilize combinations of capacitors, inductors, and resistors along with transmission lines to achieve the intended matching. One example of such a system is an LC match network comprised of an inductor “L” and capacitor “C.”
The conventional impedance matching networks typically require a relatively large amount of space to implement, particularly in sub-gigahertz applications, even in integrated solutions and particularly if the conventional network incorporates a resonator structure for harmonic termination. As such, conventional impedance matching networks may not be optimal when utilized in high-power amplifier implementations in which a relatively small package space is generally preferred or desired.